Effervescent compound.



No Drawing.

TNITED sTA'rns PATENT OFFICE.

EMERSON H. STRICKLER, OF NEW YORK, N. IL, ASSIGNOR- T0 GENERAL CHEMICALCOMPANY, A CORPORATION OF N EW YORK.

EJEFERVESCEN 1 COMPOUND.

7 '0 all whom may concern Be it known that I, EMERSON H. STRICK- LER, acitizen of the United States, and resi dent of the borough of Manhattan,city, county, and State of New York, have invented certain new anduseful Improvements in Effervescent. Compounds, of which the followingis a specification.

The object of the present invention is to make monosodium phosphateuseful in baking powder and in effervescent salts generally as an acidcomponent. The-use of this substance, whose chemical formula aside fromwater of crystallization, is said to be NaH,PO,, as the acid componentin a baking powder, has hitherto resulted in a failure because it isintensely hygroscopic. (See U. S. Patent No. 674,140,1Vlay 14, 1901,lines 93 .to 96.)

Various attempts have been made from time to time to render acid bakingpowder ingredients more stable, '5. 6., less prone to change, such ascoating them with wax or waxlike material, or treating them with starchor flour (see U. S. Patent No. 692,451, German Patent No. 144,289,British Patent No. 842 of 1911). Others have used wax or waxlikesubstances with mono-ammonium phosphate. (British Patent No. 842 of1911). Attempts to render monosodium phosphate useful as a baking powderingredient have been made by changing its chemical character byconverting it into a pyrophosphate Na I-I,P O,, or into a stilldifferent compound, l Ta I-I,P,O, by the application of heat to it above350 F., preferably 37 5 to 425 F. (U. s. Patent No. 674,140);

I have found that monosodium phosphate may be stabilized by providingthe same with an integral coating of starch or of disodium phosphate. Ihave found also that bi-carbonate of soda may be made more stable bybeing provided-with an integral coating of di-sodium phosphate.

Of course, my invention is not limited to baking powder, which is hereconsidered an effervescent salt, containing a diluent such as starch,but may be used wherever the substances above referred to may profitablybe employed in a more stable condition than heretofore.

It is, of course, obvious that I may employ the monosodium phosphatestabilized in the manner hereinafter described, together withbi-carbonate of soda in ordinary condition,

Specification of Letters Patent.

Patented Aug. 27, 1912.

Application filed (February 29, 1912; Serial No. 680,723.

with or without the addition of starch, for use in connection withbaking; or I may employ the stabilized monosodium phos phate togetherwith bi-carbonate of soda also treated as hereinafter described, with orwithout the addition of starch: or I may use such bi-carbonate of sodaas the alkali ingredient in ordinary baking powders without the use ofmonosodium phosphate.

In the following examples I have given illustrative methods for carryingout my invention. Thesemethods may, of course, be varied Within widelimits without dcparting from the spirit of my invention as set forth inthe appended claims.

Method A.--Monosodium phosphate stabilized with starch can be preparedas follows: To 800 parts crystallized monosodium phosphate add 150 partswater; heat to boiling temperature. A solution of about 54 B. (hot) isthus obtained. Add 342 parts starch and stir until the starch has allbeen worked in and the hot mixture is of a creamlike consistency. It isthen cooled. under the proper conditions to obtain a powder of 100 meshor finer and one that after having been dried at a temperature below itsfusing point is suitable without any grinding for the acid constituentof a baking powder. This fine granulation can be secured by cooling themixture by either of the following methods: (1) Agitate vigorously untilit has reached atmospheric temperature. in an apparatus designed tosecure very rapid cooling. (For such an apparatus see U. S. Patent No.915,633). Dry the mixture prepared by methods (1) or (2) beginning at atemperature of 90 F. and gradually increasing to 212 F.. The dryingshould be so conducted that the monosodium phosphate does not fuse atany stage of the drying.

Method B.Wix together 800 parts monosodium phosphate crystals, 342partsstarch and 150 parts water, and grind the mixture in a suitable millsuch as a chaser, to a 100 mesh size or finer. Dry the mixture beginningat a temperature of 90 F. and gradually increasing to 212 F. The dryingshould be so conducted that the monosodium phosphate does not fuse atanystage of the drying. Or, as I have also found, dry or nearly drymonosodium phosphate finely ground (to, say, 100 mesh) may be mixed withundried starch (which usually contains about 10% moisture) and the Wholeproperly dried as above described, when the same result'is obtained.

Method 0. Using (It-sodium ph0sphate.- 'lhoroughly wet crystallizedmono-- sodium phosphate in fine powder with a-saturated solution ofdi-sodiumphosphate at about 110 F.; remove the excess liquor immediatelyby vthe suitable use of a pressure filter or of a. centrifugal machine;when this removal has been effected, dry the residue by exposing it to atemperature of 90 F., gradually increasing the same to 212 'F.; thetemperature rise should not be so rapid as to cause any fusing at anytime. The product when properly prepared ought to contain about t% ofdi-sodium phosphate and about 96% monosodium phosphate.

NoN-rrYeRosoorIc AND GRANULAR SODIUM n1- CARBONATE. Method D.'Thoroughlywet sodium bicarbonate with a saturated solution (36 of disodiumphosphate whose temperature should not be above 110 F.; immediatelyremove the excess liquor by the suitable use of 'a pressure filter or ofa centrifugal machine; when the removal has been effected, dry theresidue at an initial temperature of 90 F.; the product when properlyprepared ought to contain about 3% disodium phos phate and about 97sodium bicarbonate.

EFFERVESCENT SALTS WITH on WITHOUT A DILUENT.

Without a diluent.

Method E.-Suitably mix the following: product of Example C 60 parts,sodium bicarbonate 40 parts.

Method F. Suitably mix the following: Sodium bicarbonate prepared as inExample D 31.5 parts, cream tartar 68.5 parts.

In both these cases the material should be preferably so granulated asto pass a 100 mesh screen and remain on a 200 mesh screen, or coarser,if conditions seem to require it. p

With a diluent.

Method G.-Suitably mix the following: product ofvExampl'e A or B 60parts, sodium bicarbonate 26 parts, dried starch 14 parts.

' Method H .Suitably mix the following:

product of Example 0 41.7 parts, sodium bicarbonate 26.0 parts, driedstarch, 32.3 parts.

To use the product of Example D in H, substitute the correspondingamount of the product of Example D for the amount of sodium bicarbonatethere directed; make a corresponding reduction in the amountof starchadded.

salt which consists in mixing starch with the hot salt solution,grinding the mixture while the whole cools to room temperature, and

then drying the result.

.7. Process of stabilizing a crystallizable salt which comprises addingstarch. to a hot solution of the crystallizable salt, working themixture and agitating the whole While it cools to room temperature.

8. Process of stabilizing monosodium phosphate which comprises addingstarch to a. hot solution of the monosodium phosphate, working themixture and agitating the whole while it cools to room temperature.

9. Process of stabilizing a crystallizable salt which comprises addingstarch to a hot solution of the crystallizable salt, working the mixtureand then rapidly cooling the same to room temperature.

10. Process of stabilizing monosodium phosphate which comprises addingstarch to a hot solution of the monosodium phosphate, working themixture, and then rapidly cooling the same to room temperature.

11. Process of stabilizing a crystallizable salt which comprisesgrinding a mixture of the crystallizable salt, starch and water topowder.

12. Process of stabilizing monosodium phosphate which comprises grindinga-mixture of monosodium phosphate, starch and water to powder.

13. Process of stabilizing monosodium phosphate which consists in addingstarch to a hot saturated solution thereof, grinding the result whilethe'whole cools to room temperature, and drying the result.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing.

witnesses. A

EMERSON H. STRIOKLER.

Witnesses FRANK F. KIRKPATRICK, LOUIS ALEXANDER.

